amd64: cpu_info: rearrange members, keep ci_mds_tmp 32-byte aligned

ci_mds_tmp needs to be 32-byte aligned, otherwise we trip a CTASSERT
in amd64/cpu.c and break kernel compilation.  However, ci_mds_tmp's
32-byte alignment is at risk: the size of schedstate_percpu is about
to change.

Move ci_curproc and ci_schedstate up just after ci_mds_buf.  This puts
ci_mds_tmp at page offset 64 with no structs ahead of it in cpu_info.
With this arrangement it should remain 32-byte aligned without much
effort.

With input from guenther@.

ok guenther@

diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index eea800a..d998017 100644 (file)
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.154 2022/11/29 21:41:39 guenther Exp $      */
+/*     $OpenBSD: cpu.h,v 1.155 2023/07/04 17:29:32 cheloha Exp $       */
 /*     $NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $     */
 
 /*-
@@ -112,10 +112,8 @@ struct cpu_info {
 #define ci_PAGEALIGN   ci_dev
        struct device *ci_dev;          /* [I] */
        struct cpu_info *ci_self;       /* [I] */
-       struct schedstate_percpu ci_schedstate; /* scheduler state */
        struct cpu_info *ci_next;       /* [I] */
 
-       struct proc *ci_curproc;        /* [o] */
        u_int ci_cpuid;                 /* [I] */
        u_int ci_apicid;                /* [I] */
        u_int ci_acpi_proc_id;          /* [I] */
@@ -129,6 +127,9 @@ struct cpu_info {
        char            ci_mds_tmp[32]; /* [o] 32byte aligned */
        void            *ci_mds_buf;    /* [I] */
 
+       struct proc *ci_curproc;        /* [o] */
+       struct schedstate_percpu ci_schedstate; /* scheduler state */
+
        struct pmap *ci_proc_pmap;      /* last userspace pmap */
        struct pcb *ci_curpcb;          /* [o] */
        struct pcb *ci_idle_pcb;        /* [o] */